I'm starting to get some algae growth in my ten gallon betta tank. Anyone have suggestions of a good tankmate that could take care of the issue? I don't want to put a pleco in because it will eventually outgrow the tank.

Algae is typically a sign of either poor water quality or too much light. test your water, and make sure ammonia, nitrites, and nitrates are all good. If that's not the issue try lessening the ammount of time your tank light is on.

Most algae eaters eat a wide variety of algae and a lot of it. Your tank might not have what they need. Once it's gone, they probably wouldn't accept prepared food, which would mean a sick fish.

well personally I would not go for an algae eater, but if you want there are otto catfish, but they need to be in groups of three to four, and a 10 gallon tank wouldn't have enough room for them to find the correct ammount of algae. And plus because they're wild caught, your chances of getting them to accept prepared foods can be slim.

Old Fish Lady might be able to help you a bit more with ideas on how to control algae...

Algae is normal and expected in a tank of water and can be a sign that you have a healthy environment...with that said-it still needs to be controlled-with anything in a closed system too much can be a bad thing even when it is a good sign

First you need to ID the algae-once you know what kind it is you will know what causes it and how to control it

Green algae on the back wall is good, algae on the plant leaves can hinder plant growth and can be bad

Most common causes are too much nutrients, too much or not enough light, the wrong lights, old lights, poor plant growth....you have to balance everything......the plants have to be able to out compete the algae for nutrients...old light bulb, wrong kelvin rating, wrong photo period and the plants can't grow well enough to out compete the algae.
Too much nutrients-are you adding plant food or just leaving left over fish food or both
The number and species of plants make a difference too

The best algae eater/controller in a closed system is the hobbyist

As posted algae eating livestock only eat some species of algae and the type of algae may not be the species they eat-regardless when you add algae eating livestock they have to be supplemented with food

In a 10g open and not divided with one Betta with live plants-good algae eating livestock (beside you) are snails, shrimp and otos-if you get otos you want at least 4-they are social fish and do best in groups and you will see more natural behavior and less stress....remember a stressed fish is a sick fish and a sick fish can make every fish sick in the tank.......

Technically yes it's large enough, depending on what type. Cory cats for example are carnivorous catfish, they can do well in groups in a ten gallon and a betta because there is room and food, but algae eating ones like ottos would need a lot more room if they were eating only algae (once again, probably the only thing they'd accept seeing as they are typically caught from the wild) seeing as they eat a lot of algae, only eat certain types of algae, and a 10 gallon wouldn't have enough of it to last long. If they accepted prepared food after the algae was gone, technically yes you could have a group of ottos in a ten gallon, but I've heard some people having trouble getting their ottos to accept blanched veggies and algae tablets. Getting rid of algae is the job of the tank keeper.